Hi Robert
First off if someone else can answer this any better please do!
Robert your text file is made up of ASCII codes.
It's my understanding that OEM & ANSI are font "Code Pages".
So really the difference between OEM & ANSI is how they are displayed or which code page is used to display the same ASCII characters.
In text files there is nothing that says which code page to use!
(sort of like difference between a text file vs word processor file)
So I don't know how UltraEdit could know which font to display between OEM & ANSI.
I believe this to be true, the first 127 ASCII characters are pretty much the same between OEM & ANSI but from 128 to 255 MAJOR differences!
OEM has it's roots back in the original IBM PC with DOS.
I remember programing in basic and getting little smiley faces to display.
And to type characters above 127 you had to hold the ALT key down and use the keypad to manually enter decimal code for the character.
Boy I'm showing my age!
I found some good info on Answers dot com, searched on "Windows code pages" also search on OEM & ANSI
http://www.answers.com/main/......=2222_1
So the bottom line is HOW the ASCII characters are displayed OEM vs ANSI and the only place this will makes a major difference is above 128 decimal or 7F hex.
Check out "ASCII Table" under the "View" pull down menu in UE.
I hope this helps, anyone else is welcome to anwser this question.